for f(x) = -2^(x-1) + 4

find f^-1(x) (Inverse then function form)

y = log-2(x-4) + 1
y = -log2(x-4) + 1
y = log2(-x+4) + 1

3 different answers from various people, which one if any is right?

Thanks


I got the 3rd answer two different ways, but now some smart people I know are saying it is the 2nd answer. That could be right since the - isnt part of the base and it is just added at end? .... I may think of some more edits very soon too.